Sater, who is Russian born, is scheduled to appear before the House Judiciary Committee days after a lawsuit was filed claiming that he had plotted to use £440m allegedly stolen from a Kazakhstan bank on a Trump Tower project in Moscow. It has also been claimed he helped hide payments made on three condominiums at the Dominick – formerly the Trump SoHo – hotel in New York.

The lawsuit filed in a Manhattan court by BTA Bank and the City of Almaty on Monday alleges that Sater had personally arranged meetings between Trump and Ilyas Khrapunov, the son of a former mayor of the Kazakh capital, to discuss possible investments.

Khrapunov’s father-in-law, Mukhtar Ablyazov, a former chairman of BTA, is accused of embezzling billions of dollars from the bank and siphoning it offshore. Michael Cohen, Trump’s former lawyer and confidante, who has cooperated with prosecutors after being arrested in the Mueller inquiry, was at one point hired to act for BTA Bank in the case.

Khrapunov is not named as a defendant in the lawsuit. Trump is not accused of being engaged in any impropriety over the BTA money.

In a statement, Sater said he denied BTA’s “baseless allegations". Ablyazov also denies wrongdoing.

Sater was also due to appear before the House Intelligence Committee this week, but this has been temporarily postponed. The Committee wants to prioritise the quizzing of FBI and Justice Department officials, and members of Robert Mueller’s team, following Attorney General William Barr’s decision that Trump will not be charged with obstruction of justice, and the Special Counsel’s conclusion that there was no collusion between the Trump team and Russia.

Despite the president’s declaration that he has been completely exonerated by Mueller, and threats of retribution against those who took part in the investigation, scrutiny by Democrat members of Congress and state prosecutors into Trump’s alleged Kremlin connections and his business interests continue.

In another example of the emphasis of investigations on the money trail, the House Financial Services Committee revealed that Deutsche Bank has started handing over documents about its dealings with Trump.

The German bank was one of the few financial institutions willing to work with Trump when others stopped dealing with him. One allegation is that Trump inflated the value of his assets to get loans from Deutsche and then used the funds to pay off other debts. In 2017 the Justice Department fined Deutsche Bank $630m (£476m) for laundering money out of Russia.

Sater, born Felix Sheferovsky, is a childhood friend of Michael Cohen. The two men were involved in the Trump Tower project in Moscow which, it has been claimed, Trump was determined to see get off the ground.

Sater was apparently convinced that Vladimir Putin would help Trump get to the White House and that he and Cohen would receive the due credit. “Can you believe two guys from Brooklyn are going to elect a president?” Sater reportedly emailed Cohen, someone briefed on the exchange told The Washington Post in 2017.

He had allegedly said, in earlier messages, that the Russian president would back the development of Trump Tower in Moscow and that this would be part of a grand plan.

“Our boy can become President of the USA and we can engineer it,” said one email, obtained by The New York Times. “I will get Putin on this program and we will get Donald elected,” said another. 

Sater had been asked by Trump to squire Donald Junior and Ivanka on a trip to Moscow during which he arranged for Ivanka to sit in Putin’s chair in the President’s office in the Kremlin. Ivanka later acknowledged that her trip to Moscow included “a brief tour of Red Square and the Kremlin”, and this may have involved sitting at Putin’s desk, although she could not quite remember whether she had done so.

Cohen had made a number of serious allegations against Trump while giving evidence to Congressional Committees, including about the Trump Tower Moscow project. He claimed that Trump had tried to build it after his US presidential campaign began, while publicly denying having done so.

Sater worked for real estate firm, Bayrock, which had a suite of offices two floors beneath the Trump Organisation’s headquarters in Trump Tower for eight years. Bayrock went into partnership with Trump on the construction of the Trump SoHo hotel. The two men appeared at ribbon cutting ceremonies for joint projects and went on business trips together and Sater used Trump Organisation business cards.

Before getting into business with Trump, Sater had been convicted, in 1991, of slashing a man with a broken cocktail glass and jailed for a year. He was prosecuted again in 1998 for his role in an investment scam in which Russian and American organised crime groups targeted the elderly, some of whom were Holocaust survivors.

Sater avoided prison (and a potential sentence of 20 years) that time by becoming an informer, eventually paying a $25,000 fine. Unsealed Justice Department documents claimed that he had provided information on al-Qaeda, the American mafia and Russian organised crime, as well as activities of foreign governments.